In addition to the ignition of a fuel-air mixture with the aid of an electrically generated ignition spark, ignition based on a laser is currently being investigated. Such an operating method and a device for carrying out the method are discussed in U.S. Pat. No. 5,756,924. Laser radiation is used to generate a plasma in the combustion chamber of the internal combustion engine which initiates the combustion process for the fuel-air mixture. To generate the plasma, a so-called breakthrough intensity, between 10−10 and 10−12 W/cm2, of the introduced radiation must be exceeded. The gas forms an optically dense plasma in the region, which then absorbs additional laser radiation. When this breakthrough intensity is exceeded, a plasma is formed which is further heated by the radiation.
A disadvantage of the related art is that a relatively large amount of energy in the form of laser radiation must be expended before the breakthrough intensity is reached.